Eventmachine talk - Dec 2007 - Some new syntax for child processes

All, I know we''re still discussing several issues regarding EM#popen,
so
just to muddy the water :-), I added a sugaring for the use case in which
you want to fork the child and be notified when it terminates.

EM.run {
  d = EM::DeferrableChildProcess.open( "ls -ltr" )
  d.callback {|response|
    puts response
  }
}


This is not appropriate, of course, for cases when the child process will
generate data periodically over a long period. For that case, we will want
to pass a block that will get yielded to when the child process emits data.

The new class does NOT yet have a method for passing data into the child
process. But that will be easy enough.
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On Dec 13, 2007 5:47 PM, Francis Cianfrocca <garbagecat10 at gmail.com>
wrote:
> All, I know we''re still discussing several issues regarding
EM#popen, so
> just to muddy the water :-), I added a sugaring for the use case in which
> you want to fork the child and be notified when it terminates.
>
> EM.run {
>   d = EM::DeferrableChildProcess.open( "ls -ltr" )
>   d.callback {|response|
>     puts response
>   }
> }
>
>
> This is not appropriate, of course, for cases when the child process will
> generate data periodically over a long period. For that case, we will want
> to pass a block that will get yielded to when the child process emits data.
>
> The new class does NOT yet have a method for passing data into the child
> process. But that will be easy enough.
>
> _______________________________________________
> Eventmachine-talk mailing list
> Eventmachine-talk at rubyforge.org
> http://rubyforge.org/mailman/listinfo/eventmachine-talk
>


--
Tony Arcieri
ClickCaster, Inc.
tony at clickcaster.com
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Whoops... sorry about the blank message.

So this could, in theory, be used with Rails + Evented Mongrel to call out
to a background process you wish to run (i.e. start a job), have Rails
return a response to the request, and then have Rails do something with the
response once complete?

That would be *extremely* useful for what we''re doing.

On Dec 13, 2007 6:42 PM, Tony Arcieri <tony at clickcaster.com> wrote:
>
>
> On Dec 13, 2007 5:47 PM, Francis Cianfrocca <garbagecat10 at
gmail.com>
> wrote:
>
> > All, I know we''re still discussing several issues regarding
EM#popen, so
> > just to muddy the water :-), I added a sugaring for the use case in
which
> > you want to fork the child and be notified when it terminates.
> >
> > EM.run {
> >   d = EM::DeferrableChildProcess.open( "ls -ltr" )
> >   d.callback {|response|
> >     puts response
> >   }
> > }
> >
> >
> > This is not appropriate, of course, for cases when the child process
> > will generate data periodically over a long period. For that case, we
will
> > want to pass a block that will get yielded to when the child process
emits
> > data.
> >
> > The new class does NOT yet have a method for passing data into the
child
> > process. But that will be easy enough.
> >
> > _______________________________________________
> > Eventmachine-talk mailing list
> > Eventmachine-talk at rubyforge.org
> > http://rubyforge.org/mailman/listinfo/eventmachine-talk
> >
>
>
>
> --
> Tony Arcieri
> ClickCaster, Inc.
> tony at clickcaster.com



--
Tony Arcieri
ClickCaster, Inc.
tony at clickcaster.com
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